A series of activated carbons (ACs) were derived from sugarcane bagasse under two activation schemes: steam-pyrolysis at 600-800℃ and chemical activation with H3PO4 at 500℃. Some carbons were treated at 400, 600℃, or for 1-3 h, and/or in flowing air during pyrolysis of acid-impregnated mass. XRD profiles displayed two broad diffuse bands centered around 2θ=23 and 43˚, currently associated with diffraction from the 002 and 100/101 set of planes in graphite, respectively. These correspond to the interlayer spacing, Lc, and microcrystallite lateral dimensions, La, of the turbostratic (fully disordered) graphene layers. Steam pyrolysis-activated carbons exhibit only the two mentioned broad bands with enhancement in number of layers, with temperature, and small decrease in microcrystallite diameter, La. XRD patterns of H3PO4-ACs display more developed and separated peaks in the early region with maxima at 2θ=23, 26 and 29˚, possibly ascribed to fragmented microcrystallites (or partially organized structures). Diffraction within the 2θ=43˚ is still broad although depressed and diffuse, suggesting that the intragraphitic layers are less developed. Varying the conditions of chemical activation inflicts insignificant structural alterations. Circulating air during pyrolysis leads to enhancement of the basic graphitic structure with destruction and degradation in the lateral dimensions.

The influences of various carbonization temperatures on electrical resistivity and morphologies of polyacrylonitrile (PAN)-based nanofiber webs were studied. The diameter size distribution and morphologies of the nanofiber webs were observed by a scanning electron microscope. The electrical resistivity behaviors of the webs were evaluated by a volume resistivity tester. From the results, the volume resistivity of the carbon webs was ranged from 5.1×10-1 Ω·cm to 3.0×10-2 Ω·cm, and the average diameter of the fiber webs was varied in the range of 310 to 160 nm with increasing the carbonization temperature. These results could be explained that the graphitic region of carbon webs was formed after carbonization at high temperatures. And the amorphous structure of polymeric fiber webs was significantly changed to the graphitic crystalline, resulting in shrinking the size of fiber diameters.